Controlled spalling technology now makes it possible to remove (“spall”) a thin (typically <100 micron or μm) substrate layer from the surface of a base substrate with near-zero thickness-direction kerf losses, and to do this multiple times on the same base substrate. The potential cost savings are enormous since (i) the thickness of the spalled substrate layer can be limited to the thickness needed for the intended devices and (ii) many substrate layers may be derived from a single wafer or ingot.
However, the fragility of the spalled substrate layers typically requires that they be supported by one or more handle substrates or flexible support layers for at least some stages of processing. A flexible support layer (e.g., some type of tape) is typically first bonded to the stressor layer side of a substrate wafer/stressor layer couple, leaving an overhang of tape which may be used to initiate spall. After spalling, an upper portion of the substrate and the stressor layer remain attached to the flexible support layer. After the desired processing is completed on the exposed (spalled) surface of the spalled layer, it is often desirable to mount the spalled layer on a permanent handle substrate and remove the flexible support layer.